The invention relates to sheet type felt suitable for use as siding or roofing underlayment or as facer for foamed insulation boards. The felt has special characteristics, is economical to make and can be manufactured on conventional felt making equipment. The felt of the invention includes cellulosic fibers, glass fibers, binder and asphalt. Prior art products for the same end use are typically made from cellolosic fibers and do not include glass fibers, although U.K. Pat. No. 1,470,098 suggests broadly that a combination of glass and cellulosic fibers may be used. Typically, prior art felt products for the same intended end uses are first manufactured on conventional felt making equipment without inclusion of asphalt and are then saturated or coated with asphalt in a separate operation in a roofing mill. By contrast, felt of the invention is made in its entirety in a felt mill using conventional felt making equipment.